Fault detecting method for rail pressure sensor in common rail system

Abstract

The invention discloses a fault detecting method for a rail pressure sensor in a common rail system. The method comprises the steps that in the starting process, the rail pressure is controlled by an electronic pressure limiting valve in an open loop mode and the situation that as the rail pressure sensor drifts, an engine can not be normally started is prevented; under the specific working station, sufficient fuel oil is provided, the target rail pressure is obtained in a table look-up mode, the control current of the electronic pressure limiting valve is set according to the target rail pressure, and the pressure value measured by the rail pressure sensor is read and stored in a corresponding internal storage; the specific working station means that oil spraying is forbidden, an accelerator is zero, and the preset time interval is met; during halt, oil does not enter, the actual rail pressure is controlled in a mode under the specific working station, and pressure data measured by the rail pressure sensor are stored; after all working station data are obtained completely, pressure features at different points are analyzed, and whether the rail pressure sensor breaks down or not is judged. Through the fault detecting method, the working state of the rail pressure sensor can be comprehensively evaluated, and therefore the fault of the rail pressure sensor can be judged out accurately and reliably.

Description

technical field [0001] The invention relates to a fault detection method for a rail pressure sensor in a common rail system, belonging to the field of internal combustion engines. Background technique [0002] In the high-pressure common rail system, the accurate measurement of the fuel pressure in the rail pipe is the starting point of the rail pressure control of the common rail system. At present, most common rail systems use pressure sensors for pressure measurement. The time drift problem of the pressure sensor has always troubled people. Figure 5 Several common fault types are listed. Fault A: Positive drift of zero point and linearity, Fault B: Negative drift of zero point and linearity, Fault C: Positive drift of linearity only, Fault D: Negative drift of linearity only, Fault E: Non-linear. [0003] Chinese patent CN102037299A discloses a method for identifying faults, especially drift of a rail pressure sensor, in a common rail injection system. This method is t...

AI Technical Summary

Problems solved by technology

In practical engineering applications, the AD sampling accuracy of the chip determines that the rail pressure sampling accuracy is about 1 bar, so the selection of reference objects is not appropriate

Also, this method cannot detect drifts where only the slope changes (such as Figure 5 Fault types C, D in

Therefore, the fault phenomenon diagnosed by this method is not comprehensive.

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